Death knight (Warcraft II)

These soldiers of darkness were created by Gul’dan to replace the slaughtered Warlock clans. Assembled from the corpses of the Knights of Azeroth slain in the last battles of the First War, these abominations were then instilled with the ethereal essence of the Shadow Council. Further empowered with magical energies culled from the slain Necrolytes, the Death Knights wield an arsenal of necromantic and elemental spells that mete out all but certain death to the enemies of the Horde.

Orgrim Doomhammer's first act as the new Warchief of the Horde was to crush the orc warlocks of the Shadow Council. He grudgingly spared the council's former master, Gul'dan, in exchange for the warlock's servitude; in turn Gul'dan promised to create a host of powerful new warriors to serve the Horde. After experimenting at length with the souls of the recently slain council members, Gul'dan successfully instilled the spirit of the Warlock Teron Gorefiend into the corpse of a fallen knight of Stormwind. Thus, the first terrifying death knight was born. Gul'dan transformed his other council members as well, creating a vast legion of unholy warriors who sowed chaos and fear throughout the land of Azeroth during the Second War.

Following Gul'dan's desertion and death, part of the Horde, including the death knights, retreated through the Dark Portal to Draenor. Most of the surviving death knights disappeared after Draenor's destruction, though some of these death knights, along with Ner'zhul's other prominent spell casters, were later captured by the Burning Legion and transformed into liches. These liches were stripped of their free will by the demon lord Kil'jaeden and were reappointed into the service of his new servant, the Lich King, in order to better assist him with his task. These liches served as Scourge spell casting hero units in Warcraft III: Reign of Chaos.

Not all of the Horde's death knights were captured by Kil'jaeden, however. Some had managed to escape, and survived in Outland. The most famous of these was Teron Gorefiend. In a quest chain beginning with Quest:Teron Gorefiend, I am..., he deceives players with a fabricated account of history that tricks them into assisting him, and this deception ultimately results in his release from eternal imprisonment. He subsequently appears as a raid boss in the Black Temple.